The gap amplification technique [1]} of the first author is a construction of both a PCP and an LTC that relies on expander graphs and concatenation and departs from the domain of low degree polynomials. Meir [2]} gave a tensor-code-based construction of LTCs that is neither related to low degree functions nor to PCPs altogether. Further works [3]}, [4]} also construct LTCs without any PCP counterpart.
